This invention relates to a device for automatic actuation of an automobile clutch for connecting and disconnecting the automobile engine with a manual shift transmission. More particularly, the invention relates to a clutch actuation arrangement having a clutch actuating servo motor operated by auxiliary power (pneumatic for example) and having a control mechanism or means for controlling the servo motor as a function of the position of the accelerator pedal and/or the speeds measured at the input to the clutch (engine speed) and at the output of the clutch (transmission input speed).
The invention is an improvement in the Automatic Clutch System of U.S. patent application Ser. No. 061,059 of Zimmermann et al., filed July 26, 1979, now U.S. Pat. No. 4,295,551 and commonly owned. The disclosure of that application is incorporated herein by reference. That application discloses apparatus for automatic actuation of an automobile clutch by means of a servo motor that is actuated by auxiliary power, whereby, during starting, the auxiliary power delivery to the servo motor is controlled so that the rotational speed of the engine remains within a preassigned range about a preassigned rotational speed that is variable as a function of the position of the accelerator pedal. In that application, the preassigned value of the rotational speed of the engine follows a curve of maximum tractive power. That is to say, the preassigned rotational engine speed in each accelerator pedal position corresponds to the engine speed which gives maximum engine torque associated with that particular position of the pedal. However, maintaining the rotational speed in the range that extends above and below the optimum speed for each pedal position necessitates relatively heavy useage of the clutch, with considerable heat generation and corresponding wear. It also leads to relatively high noise levels, and increases fuel consumption, particularly in starting from a stop.